removing an instance

Hello,

I'm trying to remove an instance.  (nothing needs to be saved, I just want to remove an instance and create a new one).   I need to do it command line in linux.  I've used this commmand before:

dbca -silent -deleteInstance -gdbName databasesid -sid databasesid

this command has worked before, but know it's saying the arguments aren't correct. as I said, I just want to wipe it out.  the db has been dropped.  an alternative would be to remove the files.  If you can tell me what files need to be removed that would help too.  Thanks.

Rae